If it's only the shin that got bumped and you know you didn't twist your ankle to tear ligaments, then your blood supply is being cut off to your ankle and foot. Which could be a blood clot, or the bump is filled with fluid which is compressing on your main artery. Which either one of those cases it may be, you need to be seen today so that you can get an x ray and have this taken care of so you don't do damage to your ankle or foot.
Good luck, If you need anything else please feel free to ask. If you found this helpful don’t forget to click the *accept* button!